//
//  WGS84TOGCJ02.m
//  PerfectProject
//
//  Created by Meng huan on 14/11/21.
//  Copyright (c) 2014年 M.H Co.,Ltd. All rights reserved.
//

#import "WGS84TOGCJ02.h"

const double a  = 6378245.0;
const double ee = 0.00669342162296594323;
const double pi = 3.14159265358979324;

@implementation WGS84TOGCJ02

#pragma mark - WGS-84坐标转GCJ-02坐标
+ (CLLocationCoordinate2D)transformFromWGSToGCJ:(CLLocationCoordinate2D)wgsLoc
{
    CLLocationCoordinate2D adjustLoc;
    
    if ([self isLocationOutOfChina:wgsLoc])
    {
        // 不在中国区，则不用转换
        adjustLoc = wgsLoc;
    }
    else
    {
        // 在中国区内，进行转换
        double adjustLat    = [self transformLatWithX:wgsLoc.longitude - 105.0 withY:wgsLoc.latitude - 35.0];
        double adjustLon    = [self transformLonWithX:wgsLoc.longitude - 105.0 withY:wgsLoc.latitude - 35.0];
        double radLat       = wgsLoc.latitude / 180.0 * pi;
        double magic        = sin(radLat);
        magic               = 1 - ee * magic * magic;
        double sqrtMagic    = sqrt(magic);
        adjustLat           = (adjustLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi);
        adjustLon           = (adjustLon * 180.0) / (a / sqrtMagic * cos(radLat) * pi);
        adjustLoc.latitude  = wgsLoc.latitude + adjustLat;
        adjustLoc.longitude = wgsLoc.longitude + adjustLon;
    }
    
    return adjustLoc;
}

#pragma mark - 判断是否在中国外，YES为是，NO为否
+ (BOOL)isLocationOutOfChina:(CLLocationCoordinate2D)location
{
    if (location.longitude < 72.004
        || location.longitude > 137.8347
        || location.latitude < 0.8293
        || location.latitude > 55.8271
        ) {
        // 不在中国区
        return YES;
    }
    
    // 在中国区
    return NO;
}

#pragma mark - 纬度校正
+ (double)transformLatWithX:(double)x withY:(double)y
{
    double lat = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * sqrt(fabs(x));
    lat += (20.0 * sin(6.0 * x * pi) + 20.0 *sin(2.0 * x * pi)) * 2.0 / 3.0;
    lat += (20.0 * sin(y * pi) + 40.0 * sin(y / 3.0 * pi)) * 2.0 / 3.0;
    lat += (160.0 * sin(y / 12.0 * pi) + 320 * sin(y * pi / 30.0)) * 2.0 / 3.0;
    
    // 校正后的纬度
    return lat;
}

#pragma mark - 经度校正
+ (double)transformLonWithX:(double)x withY:(double)y
{
    double lon = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * sqrt(fabs(x));
    lon += (20.0 * sin(6.0 * x * pi) + 20.0 * sin(2.0 * x * pi)) * 2.0 / 3.0;
    lon += (20.0 * sin(x * pi) + 40.0 * sin(x / 3.0 * pi)) * 2.0 / 3.0;
    lon += (150.0 * sin(x / 12.0 * pi) + 300.0 * sin(x / 30.0 * pi)) * 2.0 / 3.0;
    
    // 校正后的经度
    return lon;
}

@end
